YOUR E-MAIL ALERTS

MIAMI, Florida (CNN) -- John Evander Couey, the drifter arrested in the rape and murder of a 9-year-old Florida girl, admitted to investigators he buried her alive three days after he abducted her, according to newly released prosecution documents.

The statements made by Couey to detectives were part of more than 300 pages of the state's case released Thursday to the defense.

Included in the documents were Couey's confession to police as well as the medical examiner's report.

Privately, however, some investigators involved in the case said they do not believe his story, because he has admitted to smoking crack cocaine during the time he held Jessica Lunsford, who lived near the mobile home he shared with his sister and others in Homosassa Springs, a town in central Florida.

Couey entered written pleas of not guilty following a grand jury indictment in April.

But in his confession, Couey said he kept Jessica in a closet in his room while the Citrus County Sheriff's Office set up a command center not far from the mobile home.

He abducted the girl on the night of February 23 from her bedroom of her home, which is about 100 yards from the mobile home, police said.

Police previously said Couey confessed March 18, a day after he was arrested, and helped them find Jessica's body.

A large-scale search involving hundreds of volunteers had failed to find the site, only a few hundred yards from the Lunsfords' home.

He told detectives Jessica was alive when investigators came to the door while questioning neighbors about her disappearance.

"For some reason, they came to our house but they didn't come in and search, but I wished they would have cause they would have found her, but they didn't," he said.

Couey told detectives he placed her inside a garbage bag and that she lay down in the hole without a fight.

Scott Grace of the Citrus County Sheriffs Office questioned him:

Grace: "And you put her inside that hole, you knew she was going to die, didn't you?"

Couey: "Yes sir. I knew that."

Grace: "She never sobbed or nothing?"

Couey: "No, no sir, no. ..."

Grace: "And when you were throwing the dirt back on her, she never said a word?"

Couey: "... Even when I did that, she didn't say a word. Why, I don't know. I swear to God, she just -- it don't make no sense why she didn't try to get away. I mean, she had plenty of opportunities."

The medical examiner listed the cause of death as suffocation.

Couey admitted to consuming drugs and alcohol and said he was foggy on the day he abducted Jessica.

He also told detectives that he cooked her a hamburger and made her urinate in the closet to avoid being seen by his housemates.

He said he allowed her to watch television through the slightly opened closet door. He claimed she was aware of news reports about the search for her.

Suspect: 'I panicked'

The investigators who say they doubt his story say that keeping a child hidden and silent in a small mobile home is improbable.

Another law enforcement source familiar with the investigation said that in his opinion Couey would have no reason to lie.

Couey told detectives in March that he entered the Lunsford home through an unlocked door and found the child asleep in her room.

She awoke and he placed his hand over her mouth to keep her quiet. According to Couey, she said, "Can I grab a toy?"

He said he replied, "Sure, go ahead and grab it, I don't care."

The toy was a stuffed dolphin, which was later found buried with Jessica, in her arms. Her hands were tied with speaker cord.

Couey said he walked Jessica across the street to his mobile home and made her climb through his bedroom window on a ladder. Then, he said, he had sex with her and she slept in his bed that night.

The next morning, he said, he became frightened by the police searching for the child.

"You know, I was just going to let her run and she ... you know, she and I got scared and I didn't let her go," he told detectives. "I got scared. I mean 'cuz y'all and everybody showed up and I just didn't know and panicked."

He said Jessica told him her father would be looking for her.

"I just told her not to worry about it, you know," he said.

He said that Jessica asked him "when I was gonna let go, and I told her I would let her go, you know, and I had planned on letting her go, but ... I don't know why I got scared."

Couey told detectives Jessica obeyed his commands to be quiet and never tried to escape or contact any of the others who were living in the mobile by beating on the walls or making any noise.

Later, at the end of his statement to detectives, he said he wished he could go back and change things.

"You know what I am? ... I'm a convicted child molester. I didn't know what to do. You know, I got scared. I panicked. I feel guilty about it now but it's too late, you know, and I do feel for her parents."

He claimed he contemplated suicide, even going into the woods on two occasions with a rope around his neck to hang himself, but he could not do it. He also tried once in the house to hang himself, he said.

According to the medical examiner's report, there was no trauma to Jessica's body, but there was evidence of sexual assault.

During the interview, Couey was asked by Grace what he would say to Jessica if she were there.

He replied: "I'm so sorry. I'm so sorry. ... I wish you were alive and you could walk to your parents. I'm sorry."

Four other people in the mobile home were also arrested -- one on charges of nonpayment of child support and three on suspicion of obstruction of justice.

Those three people were accused of failing to tell police that Couey was living there, even though they knew there was a warrant out for his arrest for violating his probation by failing to update his address as required for sex offenders.

But that alone, prosecutors said, did not constitute a crime. They declined to file formal charges against the three.